Perpetual calendar



Jan. 5, 1960 w. E. THlBoDi-:Au

PERPETUAL CALENDAR 3 SheetsSheet l Filed Aug. l. 1957 INVENTOR- QZMM/Jan. 5, 1960 w. E. THlBoDEAu PERPETUAL CALENDAR 5 SheetsSheet 2 FiledAug. 1, 1957 INVENTOR.

Jan. 5, 1960 w. E. 'rHlBoQl-:Au 2,919,511

PERPETUAL CALENDAR Filed Aug. 1, 1957 3 Sheets-Sheet 3 Flg-f IN VEN TOR.

United States Patent O PERPETUAL CALENDAR Wilfred E. Thibotleau, FallsChurch, Va.

Application August 1, 1957, Serial No. 675,741

8 Claims. (Cl. 411-113) Y (Granted under Title 35, U.S. Code (1952),sec. 266) The invention described in the specification and claims may bemanufactured and used by or for the Government for governmental purposeswithout the payment to me of any royalty thereon.

This invention relates to calendars, and in particular to a type knownas a perpetual calendar both in the sense of being settable at any dateand inthe sense of being a finder ofthe day of the week corresponding toany given date.

The cyclic rhythm of calendar data follows a definite formula which hasbeen known and employed for centuries, and many forms of perpetualcalendars or nders have been proposed heretofore. However, none of thesehas ever come into appreciable use either because their employment hasnecessarily involved certain degrees of mental effort and were thereforedivorced from the simplicity demanded by public fancy, or the proposeddevices were too cumbersome or expensive for popular appeal.

For instance, Patent No. 2,215,020 employs several sets of tables whichmust be referred to in sequence, and the process involves mentaladdition. Furthermore, this device purports to aid the user bydistinctive marking of each 4th year of a century but does not make suchprovision for those years ending *in 00 which are not leap r years. Itis noteworthy that the patentee himself suffered from this defect whenin giving an example of a date in the year 1900 he considered it a leapyear, which it was not. In my device this cannot happen.

The device of Patent No. 1,585,470 has commendable features, but suffersfrom the defect that the months, days, centuries and years are arrangedin groups which do not present an orderly sequence, and thereforeinvolves hunting for the data. This device also leaves the burden ofdetecting leap years to the operator.

In the present invention I have provided a calendar which involves nomental effort other than to select and arrange the components of a datefrom an arrangement occurring in orderly sequence and to perform anoperation similar to the dialing of a telephone. Nomental arithmetic orreference to tables is required and even the data peculiar to leapyears, including the operation of determining whether a given year is aleap year are automatically taken care of.

It is therefore an object of the invention to provide a calendar whichindicates days of the week for given dates with a minimum ofmental'effort on the part ofthe operator. 'A further object is toprovide a calendar which automatically accounts for leap year data. Yetanother object is to provide a calendar as aforesaid which is simple andinexpensive in construction and simple and reliable in operation with aminimum of data hunting.

These and other objects are attained by the invention which may bebriefly described, in principle, as follows:

The basic formula for days of the Week depends upon a cyclic movementthrough groups of seven. This is affected by the particular month, theday of the month, the number of the century and the year of the century.A

' Patented Jan. 5, 1960 perpetual calendar in any form will involvethese four data and will have further involvements in the effect of leapyears and in the determination as to which years are leap years. Theformula is precise, however, and the computation can easily be doneentirely mentally for any given date. For instance, an index number isassociated with each month in the following manner:

Jan. Feb. Mar. Apr. May Jun. Jul. Aug. Sep. Oct. Nov. Dee.

If the year is a leap year the numbers for Jan. and Feb. are as follows:

Jan. Feb.

These numbers, as associated with the months, may be easily committed tomemory.

The second piece of data is the cardinal number representing the day ofthe month.

The third piece of data is the century index, associated with the twodigits indicating the century, and these indices are as follows, in adenite cyclic pattern 24 etc. 25 etc. 26 ete. 27 etc.

The fourth piece of data is obtained from the year of the century, bymultiplying it by 5 4 and ignoring the remainder, if any.

The four items of data are summarized as follows:

M :the month index D=the day of the month C=the century index Y=5 4 ofthe year of the century, neglecting remainder.

The number for April is 6 Casting 7s out of 24 leaves 3 The total thusfar is 6-{3=9 and casting out the 7 leaves 2 The number for the 1900s isl which added to 2 gives 3 5 4 of 04 is 5 which added to 3 gives 8Casting 7 out of 8 leaves 1 and the answer is Sunday.

As a further example take July 4, 1776.

The number for July is 6 4, being less than 7, is added to 6, totallingl0 Casting out 7 leaves 3 The number for the 1700s is 5, which added to3 totals 8 Casting out 7 leaves 1 5/ 4 of 76:95 which added to 1 totals96 Casting out 91 as a multiple of 7 leaves 5 The day of the week was,therefore, Thursday.

In the embodiment of the invention shown in the accompanying drawingsand described in the specication to follow, 1 have arranged the fourcomponents of the dates in normal sequence and associated with eachcomponent the data according to the above general formula, but in whichthe 7s have already been cast out. The separate data then range from 1to 6 and when added may involve -a further casting out of 7s which Iachieve automatically by dialing the data numbers consecutively incontinuous, clockwise motion on a seven place dial, after setting it ata zero or reference position.

In the drawings:

Fig. 1 is a top plan View of the full assembly,

Fig. 2 is a diametral section taken horizontally on Fig. 1,

Fig. 3 is a sectional View taken on the line 3-3 of Fig. 2

Fig. 4 is a top plan view of one component of the assembly, and

Fig. 5 is a fragmentary view of a detail showing the ratchetarrangement.

Referring now to the drawings by characters of reference there is showna shallow cylindrical container 1 having a bottom 2 and snugly androtatably receiving a disc 3. Disc 3 has a central cylindrical cavityreceiving a second disc 4 rotatable in the cavity and having a topsurface ush with that of disc 3. Disc 4 has two concentric, annularchannels one of which mounts an annulus 5 and another of which mounts anannulus 6, and has a central cylindrical cavity mounting a disc 7,annuli 5 and 6 and disc 7 being rotatable in their mountings.

As seen in Fig. 3, disc 3 carries the years of the century from to 99fanwise in numerical order, and diametrically opposite each year on thedisc 3, but in a separate annular region, is its associated code number.For instance, opposite 57 is the number 1, and opposite 04 is the number5. The code numbers are inverted with respect to their associated data,since, as will be seen, they will be read at the left of the assembly,while the date will be set at the right.

Disc 4 carries the century numbers, herein shown only from 16 to 24, anddiametrically opposite each is its code number. For instance, opposite16 is a blank, and 1 is opposite 19.

Annulus carries the days of the month from 1 to 31 in regular order, anddiametrically opposite each is the code number, computed as theremainder above the highest multiple of 7 in the day of the month. Forinstance, opposite 24 is the number 3 and opposite 28 there appears nonumber at all.

Annulus 6 carries the months, and diametrically opposite each is itscode number. For instance, opposite June is the number 4. Opposite Ian.and Oct. no number appears since it is not necessary to dial 0.

It will be noted that annulus 6 is somewhat wider than members 3, 4 and5, the reason being that provision is here made for leap yearadjustments. As noted above the index for I an. or Feb. is reduced by 1in a leap year. The corrections are involved only in I an. and Feb.because the basic formula makes a correction which applies from thebeginning of a leap year whereas the shift does not actually take placeuntil the last day of Feb. has been passed. The same result can beachieved by adding 6, and therefore on the year-of-thece'ntury disc 3the code number 6 is placed radially opposite each year divisible by 4,except the year 00, on a circular line underlying the month disc 6, thenumerals 6 appearing as dotted lines in Fig. 3. Opposite the year 00 acode numeral 6 also appears on disc 3 underlying disc 6 but locatedradially inward of the line of the balance of the 6s. Since these '6sare to be used only in the case of Ian. or Feb. access to them isaccordingly limited by a sector-shaped opening 1.2 in the month disc 6.Since access must be had for any of the century years, this is providedby an arcuate through opening 14 in the century disc 4, opposite andequal in extent to the span of the century years. Also, since the single6 opposite the year 00 is to appear only in connection with the centuryyears divisible by 4,

namely 16, 20 and 24, access to this 6 is limited by a series of throughopenings 16, radially aligned with said century years. It will be seenthat the years divisible by 4 except 00 will produce the number 6, anycentury will pass it through arcuate slot 14 and Ian. or Feb. willpermit its Viewing through sector 12. Similarly, the year 00 willproduce a 6, but only the centuries beginning with 16, 20, or 24, willpermit its viewing through openings 16, and only J an. or Feb. willpermit its viewing through sector 12. This takes account of the completerule for determining leap years and the computation is built into themachine itself and requires no mental effort.

For convenience and abatement of possible confusion I have provided, asseen in Fig. l, a mask consisting of annuli 17, 18 and 19 connected bybridges 19, 20, 21 and 22 the purpose of the mask being to cover thedialing code numbers but leave exposed the date components for readyfinding and arrangement. In bridges 21, 22 are provided a series ofthree windows, 23, 24, 25 in which the date considered may convenientlybe framed, either for finding purposes or day to day use as a calendar.The window 23 will frame the month, window 24 the day of the month andwindow 25 the century and century year. Preferably in manufacture, themask will be rendered i'ntegral with the container 1.

In the region of bridges 19 and 2t) is a series of opeu ings 26, 27, 2S,29 which will expose the respective dialing code numbers antipodallydisposed with respect to the respective date components appearing inwindows 23, 24, 25, and the further openings 30 and 31 which provideaccess to the additional code numbers pertaining to leap years when theyappear through sector 11.

The dialing disc 7 has seven openings 32 equally spaced on a circularline which may be engaged by a pencil or other instrument for ease ofdialing. The inner annulus 19 of the mask has, around its innerperiphery, the numbers l to 6 equiangularly spaced on 6 of sevenstations, the 7th being left blank and carrying a projection 33 servingas a stop means for the dialing pencil. To prevent back-dialing aratchet device may be employed such as spring finger 34 attached to disc4 engaging in any of 7 recesses 35 in the underside of disc 7.

The days of the week are indicated on dial 7, but are concealed byannulus 19 of the mask except when appearing under a window 36 therein.With the formula employed, Saturday, the seventh day of the week is thezero reference or starting point for dialing and, to accentuate this.distinctive marking such as a prominent circle 37 around one of theopenings 32 is provided, which must be dialed first before the otherdata are dialed.

For convenience in setting up the date, openings 38 for engagement by apencil may be provided above each date component on the discs andannuli, and slots 39 are provided in bridges 2,1, 22 to accommodate thepencil.

The invention may now be illustrated by way of example, for which thedate July 4, 1863 is selected. The date may be set in any order but withthe embodiment shown it is desirable to move discs 3 and 4 first becausethe annuli ride in these. The year 63 is readily located in the sequenceof numbers on disc 3 and moved into position in window 25. On theVopposite side of the instrument the code number 1 then appears inopening 26. In the same manner the century year 18 is easily located ondisc 4 and moved into position in window 25 alongside the number 63 toprovide the complete number 1863. Opposite 18 on disc 4 the associatedcode number 3 then appears in opening 27. Next annulus 5 is rotated tobring the number 4 into window 24 and on the opposite side of theannulus the code number 4 appears in opening 28. Next July is moved intoplace in window completing the display of the date, and the associatedIuly code nurnber, 6, appears in opening 29. Nothing appears in openings30 and 31 because 1863 was not a leap year.

To recapitulate, the dialing code numbers 1, 3, 4 and 6 now appear inopenings 26, 27, 28 and 29. The dial is now zeroed to bring Sat. intoview by dialing the position of circle 37 to the stop 33. Then the disc7 is dialed in vcombination of discs and nested annuli the entireassembly could as well comprise a system Wholly made up of superimposeddiscs of regularly decreasing diameter, however this would render moreinvolved the access to leap year data.

p Broadly the invention contemplates a system in which the input dataare arranged in orderly fashion for ready location and associatednumbers are arranged for automatic exposure along with the display ofthe date components, and an adding means is provided for furtherreducing the said associated numbers by casting out each total of sevenas it occurs. The invention also includes thel feature of completelyautomatic corrections for leap years.

It is not necessary that the code numbers be antipodally arranged withrespect to the date components, since these may be located at anyconvenient angle from the reference data and may even be closelyadjacent the same. It is even possible for the code numbers to bedisplaced at different angular distances on the respective discs andannuli.

`As shown, the device applies to dates on the Gregorian calendar, whichis now in use. However, any date can be analyzed with respect to theJulian calendar by the at all times, as 4for instance if there is asuspicion that it has been disturbed from proper setting.

It is also worth noting that the device may be used'A to check the dayof the month if the day of the week is known. In this case one dialingwill verify a correct guess, or indicate a diiference from which theresult may be inferred, and this may then be given al iinal dialingcheck, if desired.

While I have shown and described a particular embodiment of myinvention, the same is not limited thereby but may partake of various`forms and comprise equivalents obvious to those skilled in the art, andtherefore, the invention should not be deemed as limited except as shallappear from the spirit and scope of the appended claims.

I claim:

l. A calendar device comprising movable members bearing, respectively,date components representing the months of the year, cardinal numbersrepresenting the days of the month, the rst two digits of the yearnumber and the last two digits of the year number, code numbers from 1to 6 and including blanks, on each member, xed-ly associated with therespective date components thereon, and means carried by the said deviceto produce the cumulative sum of a set of said code numbers, above thehighest multiple of seven corresponding to a set of said componentsrepresenting a given date, as arranged by movement of said members, saidmeans comprising a dialing disc having seven, equiangularly spacedstations, and index means for said dialing disc, said index meanscomprising seven equiangularly spaced stations, six of which arenumbered from l to 6, and said dialing disc bearing the respective daysof the week arranged for cyclic accumulation in correspondence with theaccumulation of said code numbers.

2. A calendar device comprising movable, coaxial, cir- 6 A cular membersbearing, respectively, in normal sequence date components representingthe months of the year, cardinal numbers representing the days of themonth, the first two digits of the year number and the last two digitsof the year number, code numbers from 1 to 6 and including blanks, oneach member, iixedly associated with the respective date componentsthereon, indicator means for rendering prominent a set of said codenumbers corresponding to a set of said components representing a givendate, as arranged by movement of said members, and means carried by thesaid device to produce the cumulative sum of said set of code numbersabove the highest multiple of seven, said means bearing the days of theweek arranged for cyclic movement in unison with the numbers beingaccumulated.

3. A calendar device comprising movable, coaxial, circular membersbearing, respectively, in normal sequence, date components representingthe months of the year, cardinal numbers representing the days of themonth, the tirst two digits of the year number and the last two digitsof the year number, code numbers from 1 to 6 and including blanks, oneach member ixedly associated with the respective date componentsthereon, indicator means for rendering prominent a set of said codenumbers corresponding to a set of said components representing a givendate, as arranged by movement of said members,l and circular meanscarried by the said device to produce the cumulative sum of said set ofcode numbers above the highest multiple of seven, said circular meansbearing the days of the Week arranged for cyclic movement in unison withthe numbers being accumulated, said means comprising a coaxial dialingdisc having seven, equiangularly spaced stations, and index means forsaid dialing disc having seven equiangularly spaced stations, six ofwhich are numbered from l to 6.

4. A calendar device comprising movable members bearing, respectively,date components representing the months of the year, cardinal numbersrepresenting the days of the mo-nth, the rst two digits of the yearnumber and the last two digits of the year number, code numbers on eachmember xedly associated with the respective date components thereon,indicator means for rendering prominent a set of said code numberscorresponding to a set of said components representing a given date, andmeans carried by said device to produce through cycles having aperiodicity of seven the cumulative sum, above the highest multiple ofseven of a set of said code numbers corresponding to a set of saidcomponents representing a given date, as arranged by movement of saidmembers, said latter means bearing the days of the week arranged forcyclic movement in unison with the numbers being accumulated, the codenumbers associated with the year numbers including numbers associatedonly with leap years, said latter numbers being manifest through saidindicator means only in the cases where the selected date componentcomprises January or February, and either the year of the century,exclusive of double zero, is divisible by four, or the years ending indouble zero are divisible by four hundred.

5. A calendar device comprising a plurality of circular members arrangedfor rotation about a common center, a iirst one of said members bearingthe year numbers 00 to 99 arranged in numerical order at a fixed radialdistance and code numbers arranged in correspondence with the respectivesaid year numbers, a second one of said members bearing century numbersarranged in numerical o-rder at a lrixed, radial distance and codenumbers arranged in correspondence with the respective, said cen turynumbers, a third one of said members bearing the day-of-the-monthnumbers l to 3l arranged in numerical order at a fixed, radial distanceand code numbers arranged in correspondence with the respective, saiddayof-the-month number, a fourth one of said members bearing the namesof the months, in order, at a iixed, radial distance and code numbersarranged in correspondence with the respective said months, and means toaccumulate, through cycles of seven, the sum of those code numberscorresponding to a date selected from the four said members, anadditional code number on the said rst one of said members associatedwith each of the year numbers divisible by 4, and means to permit theviewing of said additional code number' only in the case of a dateinvolving January or February.

6. A calendar device comprising a plurality of circular members arrangedfor rotation about a common center, a first one or" said members bearingthe year numbers to 99 arranged in numerical order at a iXed radialdistance and code numbers arranged in correspondence with the respectivesaid year numbers, a second one of said members bearing century numbersarranged in numerical order at a fixed, radial distance and code numbersarranged in correspondence with the respective, said century numbers, athird one of said members bearing the day-ofthemonth numbers 1 to 3.1arranged in numerical order at a xed, radial distance and code numbersarranged in correspondence with the respective, said day-of-the-monthnumbers, a fourth one of said members bearing the names of the months,in order, at a fixed, radial distance and code numbers arranged incorrespondence with the respective said months, and means to accumulate,through cycles of seven, the sum of those code numbers corresponding toa date selected from the four said members, an additional code number onthe said rst one of said members associated with each of the yearnumbers divisible by 4, except the year 00, a further code numberassociated with the year 00, means to permit the viewing of saidadditional code numbers and said further code number only in the caseofa date involving January or February, and means to permit the viewing ofsaid further code number only in the case of a date involving a centurynumber divisible by 4.

7. A calendar device comprising a series of circular members rotatableabout a common center, the rst of said members comprising a iirst diskwith raised annulus, a second disk nested in said first member, andhaving an outer, raised annulus and two inner, raised annuli, definingan outer, annular trough, an inner, annular trough, and a central,circular, dished portion, annular members nested in said respectivetroughs, and a third disk nested in said dished portion, said lirst diskbearing the year numbers 00 to 99 arranged in numerical order on theraised annulus, and code numbers arranged in correspondence with therespective, said year numbers, said second disk bearing century numberson its raised annulus, arranged in numerical order, and code numbersarranged in correspondence with the respective, said century numbers,the annular member in said outer trough bearing the day-of-the-monthnumbers, 1 to 31, arranged in numerical order, and code numbers arrangedin correspondence with the said day-of-the-month numbers, the annularmember in said inner trough bearing the names of the months, in order,and code numbers arranged in correspondence with the respective, saidnames of the months, said third disk having seven equidistant stationsfor stepwise rotation and bearing the names of the days of the week inassociation with said stations, masking means for said device providedwith apertures for viewing the selected components of a given date asarranged by rotation of said disks and annuli, further apertures forviewing the code numbers corresponding to the selected date components,and an a'perture for viewing the corresponding day of the week asselected by dialing said third disk in accordance with the code numbersin view.

8. A calender device comprising a series of circular members rotatableabout a common center, the first of said members comprising a rst diskwith raised annulus, a second disk nested in said rst member, and havingan outer, raised annulus and two inner, raised annuli, defin-v ing anouter, annular trough, an inner, annular trough, and a central, circulardished portion, annular members nested in said respective troughs, and athird disk nested in said dished portion, said r'st disk bearing theyear numbers O0 to 99 arranged in numerical order on the raised annulus,and code numbers arranged in correspondence with the respective, saidyear numbers, said second disk bearing century numbers on its raisedannulus, arranged in numerical order, and code numbers arranged incorrespondence with the respective, said century numbers, the annularmember in said outer trough bearing the day-of-the-month numbers, 1 to31, arranged in numerical order, and code numbers arranged incorrespondence with the said day-of-the-month numbers, the annularmember in said inner trough bearing the names of the months, in order,and code numbers arranged in correspondence with the respective, saidnames of the months, said third disk having seven equidistant stationsfor stepwise rotation and bearing the names of the days of the week inassociation with said stations, masking means for said device providedwith apertures for viewing the selected components of a given date asarranged by rotation of said disks and annuli, further apertures forviewing the code numbers corresponding to the selected date components,and an aperture for viewing the corresponding day of the week asselected by dialing said third disk in accordance with the code numbersin view, the code numbers for the year numbers divisible by four beingarranged beneath said inner trough for coaction with the month data,with the code number for the year 00 dissociated from the balance of theyear code numbers, said masking means having viewing means for said yearcode numbers, said second disk having a sector slot for viewing saidyear code numbers and a series of apertures arranged for alignment withsaid year 00 code number when the selected date involves a centurynumber divisible by four, and said annular member in said inner troughhaving an aperture arranged to provide for viewing any or said year codenumbers when the date involves January or February.

References Cited in the le of this patent UNITED STATES PATENTS 584,955McLeod lune 22, 1897 903,192 Hunt Nov. 10, 1908 1,585,470 Des Nos s..May 18, 1926 1,600,874 Greenwood et al. Sept. 21, 1926 1,611,538 LandmanDec. 21, 1926 2,215,020 Sow Sept. 17, 1940

